Fuel supply system



United States Patent Inventors Richard P. Ballou 5 R f e Cited UNITEDSTATES PATENTS John A. McDougal, Flint, Michigan App]. 817,790 2,986,1335/1961 Mattson l23/l 36 il d Apr 1969 Primary Examiner-Laurence M.Goodridge Patented 1970 Attorneys-Jean L. Carpenter and Hugh L. FisherAssignee General Motors Corporation Detroit, Michigan a corporation ofDelaware ABSTRACT: A fuel supply system for transferring fuel between areservoir and an engine. The apparatus incorporates a reversibleelectric fuel pump and a pump control cir- 3 i Y EM cuit for controllingthe transfer of fuel by the pump in acrawmg cordance with the setting ofa lural setting en ine controller.

P 8 US. Cl. 123/136, The fuel pump transfers fuel to the engine tofacilitate starting l23/179; 4l7/l0 and operating the engine andwithdraws fuel from the engine Int. Cl. ..F02ln 59/42 to stop theengine. A bypass network is provided for operating Field of Search 123/136, the pump and an ignition coil at increased voltages when startl79;417/10 ing the engine.

3Z\ /\/V -fi ENGINE Z? ACC LOADS a? we ENGINE OIL PATENTEDDEE 8 I970INVIEN'I'UAS 1 wk Y nw m wwww w /m d m v m Y FUEL SUPPLY SYSTEM Thisinvention relates to fuelsupply systems and in particular toimprovements in fuel supply systems for motor vehicles in which fuel istransferred between a fuel reservoir and an engine. Fuel supply systemspresently used in motor vehicles for supplying an engine with fuel froma fuel reservoir .are unidirectional in operation as they utilize fuelpumps operable only to transfer fuel from the fuel reservoir. to ,theengine. Since the primary purpose of fuel supply systems is to transferfuel from the reservoir to the engine these prior systems performsatisfactorily when the engine is in operation. However, when the engineis stopped after a period of operation, these systems retain asignificant quantity of fuel in proximity to the engine, which fuel issubject to evaporation loss due to heat from the engine while the enginecools.

It is therefore an object of thisinvention to provide a novel fuelsupply system for an engine in which fuel is transferred from areservoir to the engine when the engine is to be operated and from theengine to the reservoir when the engine is to be stopped, the enginebeing stopped by withdrawing its supply of fuel. I v

Another object of the invention is to provide an engine fuel supplysystem capable of providing an increased quantity of power to a fuelpump when starting the engine so as to drive the fuel pump faster andthereby increase the quantity of fuel being transferred by the pump tothe engine when the engine is being started. a n

An additional object of this invention is to provide a fuel supplysystem for an engine that is particularly suited for combining with avehicle ignition network so as to enhance the operation of the vehicleignition network by providing an ignition coil with an increased voltagewhen starting the engine.

which positions enable the pump 18 to transfer fuel from the reservoir14 through a pair of conduits 22 and 24 to the engine 12. When theengine 12 is to be stopped, the ignition switch is placed in the OFFposition, which position causes the pump 18 to withdraw fuel from theengine 12 by draining the carbu= retor 16 until the engine 12 is stoppeddue to a lack of fuel.

While the pump 18 and the ignition switch 20 shown in the illustratedembodiment are electric devices, persons skilled in the artwillappreciate the reversible pumps and engine controllers of variousother types may be used in place of these units. For example, the pump18 may be replaced by a fluid driven pump and a plural setting enginecontroller utilizing fluid valves may be used in conjunction with such apump in place of the ignition switch 20. i

In the embodiment herein described the pump 18 includes'a reversible DC.motor 26 for driving the pump 18. The

a A further object of this invention is to provide a fuel supply asystem for an engine which is normally used to stop the engine bytransferring fuel from the engine to a reservoir and which includes aprovision for rapid engine restarting by not transferring fuel from theengine to the reservoir when the engine is stalled due to an overloadcondition; a n

The foregoing and 'other objects and advantages of the invention willbecome apparent from the following description and the accompanyingdrawing, in which is presented a schematic diagram of a fuel supplysystem incorporating the principles of the invention.

Referring now to the drawing, a fuel supply system 10 is provided todeliver fuel to an-engine 12 from a fuel reservoir 14. In a typicalapplication of this invention the engine 12 would be an internalcombustion engine operable to power a motor vehicle and the reservoir 14would be the vehicle's fuel tank.

In addition to the fuel reservoir 14 the fuel supply system 10 in theillustrated embodiment includes a carburetor 16 for mixing fuel with airand introducing the fuel-air mixture to the engine 12, the carburetor 16being of a conventional design that has. been modified in a fashionfamiliar to persons skilled in the art so as to permit the withdrawal offuel therefrom, a reversible electric fu'el'pump. 18 for transferringfuel between the reservoir 14 and the engine 12, a pump control circuit28 for controlling the supply of electric energy to the pump 18, and aswitch 20, e.g., an ignition switch, that is used as a plural settingengine controller. The pump 18 is operative in accordance with thesetting of the switch 20. While any reversible electric fuel pump may beused for the pump 18, the pump described in Shultz et al. US. Pat. No.3,418,991 is suggested as beingof a suitable design for use in the fuelsupply system 10 and can be, as will be understood by those versed inthe art, made to rotate in either. direction by reversing the armatureconnections.

The ignition switch. 20 may be of any conventional design presentlyfound in motor vehicles. In the illustrated embodiment it is of a typehaving OFEON, and START positions to obtain engine off, engine on, andengine starting conditions, respectively. When theengine 12 is to beoperated the ignition direction and rate of fuel transfer by the pump 18are dependentupon the polarity and the magnitude of electric energysupplied to the motor 26. The pump control circuit 28 con' trols thesupply of electric energy to the motor 26 in accordance with theignition switch 20 position.

The pump controlcircuit 28 is powered by an electric power source, shownas a battery 30 in the drawing, and includes a pump energization networkv32 for providing energization of the motor 26 by the battery 30, adirection control network 34 for controlling the motor 26 polarity inthe pump energization network 32 so as to control the direction in whichthe pump 18 transfersfuel when the motor 26 is energized,

and a bypass network 36 for providing the motor 26 with an increasedquantity of electric energy when starting the engine 12. It should benoted at this point that the directioncontrol network 34 does not itselfprovide energization of the motor 26 but merely controls the motor 26polarity in the pump energization network 32 so as to control thedirection in which the motor 26 drives the pump 18 when the motor 26 isener- Qgized by the pump energization network 32.

The pump energization network 32 includes the motor 26, a

fuse 38 for protecting the circuits from excessive currents, a

voltage limiting resistor 40 for reducing the. voltage applied to themotor 26 by the battery 30 and for protecting the motor 26 from currentsurges produced by reversing the motor 26 polarity in the pumpenergization network 32 when the motor 26 is energized, and an engineresponsive switch 42 for completing a current path from the battery 30through the voltage limiting resistor 40 and thefuse 38 to the motor 26.For reasons which will be later explained. The motor 26 is energizedthrough the voltage limiting resistor 40 only when theengine 12 is inoperation. The engine responsive switch 42 is therefore selected to beof a type that is closed when the engine 12 is in operation and openwhen the engine 12 is stopped. As persons skilled in the art willappreciate, several parameters of the engine 12, such as oil pressure,engine coolant pressure, and engine speed may be used to close theengine responsive switch 42 when the engine 12 is in operation and openthe engineresponsive switch 42 when the engine 12 is stopped. In. theillustrated embodiment the engine responsive switch 42.is shown to be ofa type responsive to the engine 12 oil pressure. a The direction controlnetwork 34 includes a direction control relay 44 having a winding 45 anda plurality of contacts 46, 48,50, and 52. Energization of the directioncontrol relay 44 is controlled by the switch 20, which in theillustrated embodiment includes a .wiper 54 and a plurality of terminals56, 58, 60, and 62. The wiper 54 and the tenninals 56, 58, 60, and 62are of electrically conductive material, such as copper, and serve tocomplete various current paths through the switch 20. The directioncontrolrelay 44 is deenergized by placing the switch 20. in the OFFposition so as to connect the direction control relay 44 to groundthrough a lead 64, the terminal 62, the wiper 54, and the terminal 56.When the direction control relay 44 is deenergized the contacts 48 and52 are closed so as to connect the motor 26 in the pump energizationnetwork 32 according to the polarity indicated in the drawing. The pump18 can only transfer fuel from the engine 12 to the reservoir 14 whenthe motor 26 is connected in the pump energization network 32 accordingto this polarity.

The direction control relay 44 is energized by placing the ignitionswitch in the ON or START position, which connects the direction controlrelay 44 to the battery 30 through the lead 64, the terminal 62, thewiper 54, the terminal 58, and a lead 66. When the direction controlrelay 44 is energized the contacts 48 and 52 are open and the contacts46 and 50 are closed so as to connect the motor 26 in the pumpenergization network 32 according to a polarity opposite that shown inthe drawing. Energizing the direction control relay 44 thus connects themotor 26 in the pump energization network 32 according to the polarityrequired for the pump 18 to transfer fuel from the reservoir 14 to theengine 12.

The bypass network 36 provides an increased voltage to the motor 26 whenstarting the engine 12 by completing a low impedance current path fromthe battery 30 to the fuse 38 so as to bypass the engine responsiveswitch 42 and the resistor 40. Virtually the entire battery 30 voltageis applied to the motor 26 when the voltage limiting resistor 40 isbypassed. By applying the entire battery 30 voltage to the motor 26 whenstarting the engine 12, the pump 18 is driven faster and transfers anincreasedquantity of fuel to the carburetor 16, reducing the timerequired for fuel to be introduced to the engine 12. This feature isespecially useful after the engine 12 has been turned off by using thepump 18 to empty the carburetor 16 of fuel.

The bypass network 36 is actuated by placing the ignition switch 20 inthe START position. Placing the ignition switch 20 in the START positionenergizes a starting relay 68 by completing a current path from thebattery 30 through the lead 66, the terminal 58, the wiper 54, theterminal 60, a lead 70 and the starting relay 68. When the startingrelay 68 is energized it closes a set of contacts 72 so as to completethe bypass network 36 from the battery 30 through the lead 66, theterminal 58, the wiper 54, the terminal 62, the lead 64, a lead 74, thecontacts 72, and a lead 76 to the fuse 38. It is thus apparent that themotor 26 is provided with an increased voltage through the bypassnetwork 36 when the engine 12. is being started.

The starting relay 68 may also be provided with sets of contacts 78 and80 for combining the pump control circuit 28 with the various accessorydevices presently found in motor vehicles and a conventional ignitionnetwork 82. When the starting relay 68 is energized by placing theignition switch 20 in the START position the contacts 78 are opened andthe contacts 80 are closed. Opening the contacts 78 relieves the battery30 of excessive current drain when starting the engine 12 by opening thecurrent paths to the various accessory devices in the vehicle whileclosing the contacts 80 provides for supplying the engine 12 withignition energy when starting the engine 12, as will now be explained.

As in disclosed in the drawing, the ignition network 82 and the pumpcontrol circuit 28 may be combined by connecting the ignition network 82in series with the switch 42 and the battery 30. The ignition network 82is comprises of an ignition coil 84 for producing ignition pulses and avoltage dropping resistor 86 for limiting the voltage applied to thecoil 84 through the engine responsive switch 42 to a level less than thebattery 30 voltage. In a typical installation this voltage isapproximately one-half the battery 30 voltage. Since the engineresponsive switch 42 is closed by the engine 12 oil pressure, the coil84 is only energized through the voltage dropping resistor 86 when theengine 12 is in operation. The coil 84 is energized by the bypassnetwork.36 through the contacts 80 when starting the engine 12.

As was previously explained with regard to energization of the motor 26,placing the ignition switch 20 in the START position connects the lead64 to the battery 30 through the ignition switch 20 and also energizesthe starting relay 68. When the starting relay 68 is energized it closesthe contacts 80 so as to connect the lead 64 to the coil 84 through alead 88 and a lead 90. Virtually the entire battery 30 voltage is thusapplied to the coil 84 when starting the engine 12. The increasedvoltage applied to the coil 84 enables the coil 84 to provide anincreased ignition pulse to the engine 12 so as to facilitate startingthe engine 12.

The operation of the fuel supply system 10 will now be explained. Whenthe engine 12 is stopped and the ignition switch 20 is in the OFFposition the pump control circuit 28 is deenergized and the pump 18 isnot transferring fuel. When'it is desired to start the engine 12 theignition switch 20 is placed in the START position so as to cause thebattery 30 to energize the relays 44 and 68 through the lead 66, theterminal 58, the wiper 54, the terminals 60 and 62, and the leads 64 and70, respectively.

When the direction control relay 44 is energized it closes the contacts46 and 50 so as to connect the motor 26 in the pump energization network32 according to the polarity needed for the pump 18 to transfer fuelfrom the reservoir 14 to the carburetor 16. When the starting relay 68is energized it opens the contacts 78 so as to reduce the load placed onthe battery 30 by the various accessory loads in the vehicle and closesthe contacts 72 and 80 so as to permit energization of the motor 26 andthe ignition coil 84 through the lead 64, which is at the battery 30voltage. The pump 18 is thus driven so as to transfer fuel from thereservoir 14 to the carburetor 16 and the ignition coil 84 is madeoperative to supply ignition energy to the engine 12 while the engine 12is being cranked in a conventional fashion, as by using a startingmotor.

Once the engine 12 has been started the ignition switch 20 is placed inthe ON position so as to deenergize the starting relay 68. Deenergizingthe starting relay 68 causes it to close the contacts 78 so as toconnect the various vehicle accessory devices to the battery 30 throughthe lead 64 and opens the contacts 72 and 80 so as to permitenergization of the motor 26 and the coil 84 through the engineresponsive switch 42 and the resistors 40 and 86, respectively.

As persons skilled in the art will appreciate, it is necessary that thecontacts 72 and 80 remain closed at least until the engine responsiveswitch 42 closes so as to continue the encrgization of the motor 26 andthe ignition coil 84 without interruption. To assure that energizationof the motor 26 and the coil 84 is not interrupted, the starting relay68 may be of a slow-release-type that does not drop out until a briefperiod has elapsed after it is deenergized. Since the engine responsiveswitch 42 closes very fast when the engine 12 is started, preventing thestarting relay 68 from dropping out for approximately one second hasbeen found to be sufficient to assure that the engine responsive switch42 is closed before the contacts 72 and 80 are opened.

When the contacts 72 and 80 open, the resistors 40 and 86 reduce thevoltages applied to the motor 26 and the ignition coil 84 to less thanthe battery 30 voltage. The motor 26 and the ignition coil 84 aretherefore designed for operation at voltages less than the battery 30voltage and use of the bypass network 36 when starting the engine 12pennits driving the motor 26 and the ignition coil 84 at voltages inexcess of their design voltages so as to increase the transfer of fueland ignition energy to the engine 12 when the engine 12 is beingstarted. Because of the short time in which an increased voltage isapplied to the motor 26 and the coil 84 when starting the engine 12, nodamage to these units results from applying the increased voltages tothem.

When it is desired to stop the engine 12 the ignition switch 20 isplaced in the OFF position as shown in the drawing, deenergizing thedirection control relay 44 by connecting it to ground through the lead64, the terminal 62, the wiper 54, and the terminal 56. When thedirection control relay 44 is deenergized it reverses the polarity ofthe motor 26 in the pump energization network 32, causing the pump 18 totransfer fuel from the engine 12 to the reservoir 14. Since the ignitionnetwork 82 continues to be energized by the battery 30 through theengine responsive switch 42 so long as the engine 12 is in operation,the engine 12 continues to operate until it runs out of fuel. When theengine 12 stops it loses its oil pressure and opens the engineresponsive switch 42. Opening the switch 42 deenergizes both the pumpcontrol circuit 28 and the ignition network 82.-

The vehicle operator may restart the engine 12 simply by turning theignition switch to the START position as previously described.

Should the engine 12 oil pressure be lost due to stalling or some otherreason prior to placing the ignition switch 20 inthe OFF position, theengine responsive switch 42 will open as soon as the engine 12 oilpressure releases it. When the engine responsive switch 42 is opened itdeenergizes the pump control circuit 28 and the motor 26 so as to stopthe transfer of fuel and ignitionenergy to theengine 12. Since fuelisnot withdrawn from the engine l2 by the pump 18 prior to the en-' ginel2 stalling, the engine 12 may be immediately restarted after a stallwithout having to wait until the pump 18 has filled the carburetor 16with fuel.

While many variations of this invention will be apparent to thoseskilled in the art it is understood that the invention is to be limitedonly by the following claims.

We claim:

1. In a fuel supply system for an engine, the combination of a pluralsetting enginecontroller, a fuel reservoir, a reversible fuel pump fortransferring fuel between the engine and the reservoir, a power sourcefor driving the pump, and pump control means operative to control thedrive direction of the fuel pump by the power source in accordance withthe setting of the engine controller so that when the engine is to beoperated the pump supplies fuel to the engine and when the engine is tobe stopped the pump withdraws fuel from the engine.

2. In a fuel supply system for an engine, the combination of a fuelreservoir, a reversible fuel pump for transferring fuel between theengine and the reservoir, a power source for driving the pump, a pluralsetting engine controller, and pump control means for controlling thesupply of power from the power source to the pump, the pump controlmeans including direction control means operative to control the drivedirection of the fuel pump by the power source in accordance with thesetting of the engine controller so that when the engine is to beoperated the pump supplies fuel to the engine and when the engine is tobe stopped the pump withdraws fuel from the engine.

3. In a fuel supply system for an engine, the combination of a pluralsetting engine c0ntroller,'a fuel reservoir, areversible fuel pump fortransferring'fuel between the engine and the reservoir, a power sourcefor driving the pump, and pump control means for controlling the supplyof power to the pump, the pump control means including direction controlmeans operative to control the drive, direction of the fuel pump by thepower source in accordance with the setting of the engine controller sothat when the engine is to be operated the pump supplies fuel to theengine and when the engine is to be stopped the pump withdraws fuel fromthe engine and bypass means also operative in accordance with thesetting of the engine controller so as to increase the power supplied tothe pump when the engine is to be started.

'4. In a fuel supply system for an engine, the combination of a fuelreservoir, a reversible electric pump for transferring fuel between thereservoir and the engine, a power source for driving the pump, a pluralsetting engine controlling switch, and a pump control circuit forcontrolling the supply of power from the power source to the pump so asto drive the pump in accordance with the setting of the enginecontrolling switch so that when the engine is to be operated the pumpsupplies fuel to the engine and when the engine is to be stopped thepump withdraws fuel from the engine, the pump control circuit includinga bypass network also operative in accordance with the setting of theengine controlling switch so as to increase the power supplied to thepump when the engine is to be started. i

5. In a fuel supply system for an engine, the combination of a pluralsetting engine controlling switch including engine On, engine Ofi, andengine Starting settings, a fuel reservoir, a reversible electric pumpfor transferring fuel between the reservoir and the engine, a powersource for driving the pump, and a pump control circuit for controllingthe supply of power to the pump from the power source, the pump controlcircuit including a pump energization network for controlling theenergization of the pump by the power source in accordance with thesetting of the engine controlling switch and the engine operation sothat when the engine controlling switch is in the engine Off or engineOn position and the engine is in operation orwhen the engine controllingswitch is in the engine Starting position the power source energizes thepump, and a direction control network operative in accordance with thesetting of the engine controlling switch so that when the enginecontrolling switch is in the engine On or engine Starting position thepump may be energized by the power source for operation in a directionto supply fuel to the engine and when the engine controlling switch isin the: engine Off position the pump may be energized by the powersource for operation in a direction to withdraw fuel from the engine.

6. In a fuel supply system for an engine, the combination of a pluralsetting engine controlling switch including engine On, engine Off, andengine Starting settings, a fuel reservoir, a reversible electric pumpfor transferring fuel between the reservoir and the engine, a powersource for driving the pump, and a pump control circuit for controllingthe supply of power to the pump from the power source, the pumpcontrolcircuit including a pump energization network for controlling theenergization of the pump by the power source in accordance with thesetting of the engine controlling switch and the engine operation sothatwhen the engine controlling switch is in the engine Off or engine Onposition and the engine is in operation or when the engine controllingswitch is in the engine Starting position the power source energizes thepump, and a direction control network operative :in accordance with thesetting of the engine controlling switch so that when the enginecontrolling switch is in the engine On or engine Starting position thepump may be energized by the power source for operation in a directionto supply fuel to the engine and when the engine controlling switch isin the engine Off position the pump may be energized by the power sourcefor operation in a direction to withdraw fuel from the engine, and abypass network also operative in accordance with the setting of theengine controlling switch so as to increase the power supplied to thepump when starting the engine.

7. In a fuel supply system for an engine, the combination of a pluralsetting engine controlling switch including engine On, engine Off, andengine Starting settings, a fuel reservoir, a reversible electric pumpfor transferring fuel between the reservoir and the engine, a powersource for driving the pump, and a pump control circuit for controllingthe supply of power to the pump from the power source, the pump controlcircuit including a pump energization network for controlling theenergization of the pump by the power source in accordance with thesetting of the engine controlling switch and the engine operation sothat when the engine controlling switch is in the engine Off or engineOn position and the engine is in operation or when the enginecontrolling switch is in the engine Starting position the power sourceenergizes the pump, the pump energization network including a voltagelimiting resistor and an engine responsive switch in series with thepump and the power source for supplying the pump with a reduced voltagefrom the power source when the engine is in operation, a directioncontrol network for controlling the direction direction to withdraw fuelfrom the engine, and a bypass network operative in accordance with thesetting of the engine controlling switch so as to increase the powersupplied to the pump when starting the engine by increasing the voltageapplied to the pump. j

8. In a fuel supply system for an engine, the combination of a pluralsetting engine controlling switch including engine On, engine off, andengine Starting settings, a fuel reservoir, a reversible electric pumpfor transferring fuel between the reservoir and the engine, a powersource for driving the pump, and a pump control circuit for controllingthe supply of power to the pump from the power source, the pump controlcircuit including a pump energization network for controlling theenergization of the pump by the power source in accordance with thesetting of the engine controlling switch and the engine operation sothat when the engine controlling switch is in the engine Off or engineOn position and the engine is in operation or when the enginecontrolling switch is in the engine Starting position the power sourceenergizes the pump, the pump energization network including a voltagelimiting resistor and an engine responsive switch in series with thepump and the power source for supplying the pump with a reduced voltagefrom the power source when the engine is in operation, a directioncontrol network for controlling the direction in which the pumptransfers fuel, the direction control network including a directioncontrol relay in series with the engine controlling switch and the powersource for controlling the polarity of the pump in the pump energizationnetwork in accordance with the setting of the engine controlling switchso that when the engine controlling switch is in the engine On or engineStarting position the pump may be energized by the power source foroperation in a direction to supply fuel to the engine and when theengine controlling switch is in the engine Off position the pump may beenergized by the power source for operation in a direction to withdrawfuel from the engine, and a bypass network for increasing the powersupplied to the pump when starting the engine, the bypass networkincluding a starting relay for closing a low resistance current pathfrom the power source to the pump in accordance with the setting of theengine controlling switch so that when the engine controlling switch isin the engine Starting position the power supplied to the pump isincreased by increasing the voltage applied to the pump.

9. In a fuel supply system for an engine, the combination of a fuelreservoir, a reversible fuel pump for transferring fuel between thereservoir and the engine, a power source for driving the pump, a pluralsetting engine controller, pump control means for controlling the supplyof power to the pump, the pump control means including direction controlmeans operative to control the drive direction of the fuel pump by thepower source in accordance with the setting of the engine controller sothat when the engine is to be operated the pump supplies fuel to theengine and when the engine is to be stopped the pump withdraws fuel fromthe engine, and ignition means for supplying ignition energy to theengine, the ignition means being energized by the power source, the pumpcontrol means also including bypass means operative in accordance withthe setting of the controller so as to increase the power supplied toboth the pump and to the ignition means when the engine is to bestarted.

10. In a fuel supply system for an engine, the combination of a fuelreservoir, a reversible electric pump for transferring fuel between thereservoir and the engine, a power source for driving the pump, a pluralsetting engine controlling switch, a pump control circuit forcontrolling the supply of power from the power source to the pump so asto drive the pump in accordance with the setting of the enginecontrolling switch so that when the engine is to be operated the pumpsupplies fuel to the engine and when the engine is to be stopped thepump withdraws fuel from the engine, and an ignition network forsupplying ignition energy to the engine, the ignition network includingan ignition pulse producing ignition coil energized by the power source,the pump control circuit including a bypass network operative inaccordance with the setting of the engine controlling switch so as toincrease the power supplied to both the pump and to the ignition coilwhen the engine is to be started.

11. In a fuel supply system for an engine, the combination of a pluralsetting engine controlling switch including engine On, engine Ofi, andengine Starting settings, a fuel reservoir, a reversible electric pumpfor transferring fuel between the reservoir and the engine, a powersource for driving the pump, a pump control circuit for controlling thesupply of power to the pump from the power source, the pump controlcircuit including a pump energization network for controlling theenergization of the pump by the power source in accordance with thesetting of the engine controlling switch and the engine operation sothat when the engine controlling switch is in the engine Off or engineOn position and the engine is in operation or when the enginecontrolling switch is in the engine Starting position the powersource'energizes the pump, and a direction control network operative inaccordance with the setting of the engine controlling switch so thatwhen the engine controlling switch is in the engine On or engineStarting position the pump may be energized by the power source foroperation in a direction to supply fuel to the engine and when theengine controlling switch is in the engine Off position the pump may beenergized by the power source for operation in a direction to withdrawfuel from the engine, and an ignition network for supplying ignitionenergy to the engine, the ignition network including an ignition pulseproducing ignition coil energized by the power source, the pump controlcircuit also including a bypass network operative in accordance with thesetting of the engine controlling switch so as to increase the powersupplied to both the pump and to the ignition coil when the engine is tobe started.

12. In a fuel supply system for an engine, the combination of a pluralsetting engine controlling switch including engine On, engine Off, andengine Starting settings, a fuel reservoir, a reversible electric pumpfor transferring fuel between the reservoir, and the engine, a powersource for driving the pump, a pump control circuit for controlling thesupply of power to the pump from the power source, the pump controlcircuit including a pump energization network for controlling theenergization of the pump by the power source in accordance with thesetting of the engine controlling switch and the engine operation sothat when the engine controlling switch is in the engine Off or engineOn position and the engine is in operation or when the enginecontrolling switch is in the engine Starting position the power sourceenergizes the pump, the pump energization network including a voltagelimiting resistor and an engine responsive switch in series with thepump and the power source for supplying the pump with a reduced voltagefrom the power source when the engine is in operation, and a directioncontrol network for controlling the direction in which the pumptransfers fuel in accordance with the setting of the engine controllingswitch so that when the engine controlling switch is in the engine On orengine Starting position the pump may be energized by the power sourcefor operation in a direction to supply fuel to the engine and when theengine controlling switch is in the engine Off position the pump may beenergized by the power source for operation in a direction to withdrawfuel from the engine, and an ignition network for supplying ignitionenergy to the engine in accordance with the setting of the enginecontrolling switch and the engine responsive switch so that when theengine controlling switch is in the engine Off or engine On position andthe engine responsive switch is closed or when the engine controllingswitch is in the engine Starting position the ignition network suppliesignition energy to the engine, the ignition network including anignition pulse producing ignition coil energized by the power source,the pump control circuit also including a bypass network for increasingthe power supplied to both the pump and to the ignition coil whenstarting the engine in accordance with the setting of the enginecontrolling switch so that when the engine controlling switch is in theen gine Starting position the power supplied both to the pump and to theignition coil is increased by supplying an increase voltage both to thepump and to the ignition coil.

13. In a fuel supply system for an engine, the combination of a pluralsetting engine controlling switch including engine On, engine Off, andengine Starting settings, a fuel reservoir, a reversible electric pumpfor transferring fuel between the reservoir and the engine, a powersource for driving the pump, a pump control circuit for controlling thesupply of power to the pump from the power source, the pump controlcircuit including a pump energization network for controlling theenergization of the pump by the power source in accordance with thesetting of the engine controlling switch and the engine operation sothat when the engine controlling switch is in the engine Off or engineOn position and the engine is in operation or when the enginecontrolling switch is in the engine Starting position the power sourceenergizes the pump, the pump energization network including a voltagelimiting resistor and an engine responsive switch in series with thepump and the power source for supplying the pump with a reduced voltagefrom the power source when the engine is in operation, and a directioncontrol network for controlling the direction in which the pumptransfers fuel, the direction control network including a directioncontrol relay in series with the engine controlling switch and the powersource for controlling the polarity of the pump in the pump energizationnetwork in accordance with the setting of the engine controlling switchso that when the engine controlling switch is in the engine On or engineStarting position the pump may be energized by the power source foroperation in a direction to supply fuel to the engine and when theengine controlling switch is in the engine Off position the pump may beenergized by the power source for operation in a direction to withdrawfuel from the engine, and an ignition network for supplying ignitionenergy to the engine, the ignition network including an ignition pulseproducing ignition coil and a voltage dropping resistor in series withthe engine responsive switch and the power source so as to supply theignition coil with a reduced voltage from the power source, the pumpcontrol circuit also including a bypass network for increasing the powersupplied to both the pump and to the ignition coil when starting theengine, the bypass network including a relay for closing low impedancecurrent paths from the power source to both the pump and to the ignitioncoil in accordance with the setting of the engine controlling switch sothat when the engine controlling switch is in the engine Startingposition the power supplied both to the pump and to the ignition coil isincreased by supplying an increased voltage both to the pump and to theignition coil.

